I've
tried this lens twice. It is a popular lens today because of it's huge
zoom range, light weight and low price.

I didn't like it
because of the circus-mirror like distortions at the long end and the
focus errors I saw on one sample at 70mm on my F100. There are better
choices.

Oddly it appears
to be identical to the Tamron because not only are all the specs and
optical formula identical, but it has has more in common with the Tamron
70-300 than it does with other Nikkor lenses.

For instance, it
has no index mark against which to read the focal length or focus setting,
unlike all other Nikkors, but the same as the Tamron.

It has one internal
dinky element in the variator (zoom) section of ED glass, the exact
same element as the Tamron, unlike all ED Nikkors which have usually
several of the large front primary elements of ED glass, where it counts
and is expensive. And of course, just look at the cross sectional diagrams
for the two lenses and you'll find that they are identical. Nikon realized
we were figuring this out, so some of the diagrams will show the zoom
set to a different setting which rearranges the groups in the variator
section to make the design look different to the casual observer.

Not that there's
anything wrong with this.

Nikon makes all
their own lenses in their own factory with their own glass. It's sad
to see so many stupid people buy an F5 and put a dinky discount lens
on it, since the entire point of buying a Nikon camera is to use Nikon
lenses.

If you ever hear
salesman in a camera store try to tell you that Tokina (or Tamron or
Sigma or Spooginar or Amway or anyone) really makes the lenses for Nikon,
just walk out. That's the oldest trick in the book for trying to sell
you a discount lens at a fatter markup for the salesman. (See that explained
here.)

In this one case
I think it's true. Even if it is, I'd certainly buy the Nikon-branded
version over the slightly less expensive Tamron original just for resale
value and looks. Of course I see Tamron has just introduced a newer
version of this with 1:2 macro capability, but remember that the more
things you ask any lens (or anything) to do, the less well it gets done.

On the other hand,
Nikon makes great lenses. Their expertise is not in making $250 zoom
lenses. Nikon makes fantastic $10,000 super telephotos, they make the
lenses that are used in manufacturing sub-micron computer chips, they
make $100,000 HDTV camera lenses and just about anything else you can
imagine optically. It makes sense if they choose to do a buy-resale
of an inexpensive zoom from a lower-end manufacturer known more for
it's expertise in discount products and closed-circuit TV camera lenses
than for Nikon to try to compete on the low end against companies who
do this as their primary business.

Of course Nikon
will never admit this and I don't care enough to research it any deeper.
I was not able to get anyone at Nikon USA to answer yes to the question
"is the 70-300 manufactured in a factory owned by Nikon?"
They would claim that it's "made by Nikon," but legally if
it's made in a factory owned by Tamron under contract to Nikon, then
it is "made by Nikon." Tamron USA of course also was not at
liberty to discuss this.

Of course no one
should care who makes it. This is just for all you conspiracy theorists
out there.

The cheaper 70-300
G lens appears to have the same optics, however with a plastic (not
metal) mount and no aperture ring for use with manual focusing cameras.
No, I have no idea how they compare.

Specifications

It has a great
9-bladed diaphragm, just like the Tamron. It's 2.9" (74mm) around
by 4.6" (117mm) long. It only weighs 18oz (520g).

It has thirteen
elements in nine groups.

It focusses down
to 5 feet or 1.5m, which is pretty good.

It takes 62mm filters.
The Tamron takes 58mm filters; I presume that obviously the filter thread
was changed to the Nikon standard 62mm along with the other cosmetic
changes.

This 70-300 has
circus-mirror-like distortion at the 200mm and 300mm settings, and one
of two samples had sharpness-robbing focus errors
on my F100 at the short end. OK, I'm exaggerating about the circus
mirrors, but just don't try to photograph anything with straight lines
at the long end of this zoom. The older 75-300
is far better this way.

Focus
errors mean that on my F100 that the autofocus system consistently
focussed too close at the 70mm end with one of the two samples. That
means that the images were always softer than they should have been
at 70mm with one of two lenses. This is caused by spherical aberration
and how it fools the AF system into focussing at the wrong distance.
You could focus manually, however I prefer to choose a different lens
instead, like the 70-210mm f/4-5.6D AF.

There is very little
distortion at 70mm, so shoot here if you need to keep straight lines
straight. There is pincushion distortion at 135mm, and a lot of pincushion
distortion at 200 and 300mm.

If the focus is
OK it is sharp at 70mm through 135mm. With only an f/5.6 aperture and
light weight I was unable to get consistently sharp results handheld
on Velvia at 300mm due to the long shutter speeds. I don't know if the
lens is good or not here.

I strongly recommend
the fantastic and recently discontinued 70-210mm
f/4-5.6D AF lens instead. I've seen these selling for $200 on close
out mail order. The only thing the 70-210 doesn't do is zoom out quite
as far, but it does everything else far better for less money in a better-built
lens that is true Nikon.

If you really
want to go to 300mm (not really that much different from the honest
210mm you get from the 70-210) then look for a used older AF Nikkor
75-300mm f/4.5-5.6 which go for about $225 used. It's built better,
it's bigger, photodo.com
says it's much sharper, and it's real Nikon.

Also consider the
seemingly identical 70-300 G lens. Don't fret
over the ED vs. non ED, I suspect they both have the same glass. This
lens, even though called ED, really doesn't have the important elements
made of ED glass anyway. I suspect that ED is just used as a marketing
ploy to win business away from discount brands on this lens.

So, unfortunately
I'm really not very excited about this popular lens. Save your money
and get an f/2.8.